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Drought‐Stimulated Activity of Plasma Membrane Nicotinamide Adenine Dinucleotide Phosphate Oxidase and Its Catalytic Properties in Rice
Author(s) -
Duan ZhuangQin,
Bai Lei,
Zhao ZhiGuang,
Zhang GuoPing,
Cheng FangMin,
Jiang LiXi,
Chen KunMing
Publication year - 2009
Publication title -
journal of integrative plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.734
H-Index - 83
eISSN - 1744-7909
pISSN - 1672-9072
DOI - 10.1111/j.1744-7909.2009.00879.x
Subject(s) - nicotinamide adenine dinucleotide phosphate , nadph oxidase , chemistry , reactive oxygen species , oxidase test , oxidative stress , enzyme , biochemistry , antioxidant , phosphate , enzyme assay
The activity of plasma membrane (PM) nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and its catalytic properties in rice was investigated under drought stress conditions. Drought stress led to decreased leaf relative water content (RWC) and, as a result of drought‐induced oxidative stress, the activities of antioxidant enzymes increased significantly. More interestingly, the intensity of applied water stress was correlated with increased production of H 2 O 2 and O 2 − and elevated activity of PM NADPH oxidase, a key enzyme of reactive oxygen species generation in plants. Histochemical analyses also revealed increased H 2 O 2 and O 2 − production in drought‐stressed leaves. Application of diphenylene iodonium (DPI), an inhibitor of PM NADPH oxidase, did not alleviate drought‐induced production of H 2 O 2 and O 2 − . Catalysis experiments indicated that the rice PM NADPH oxidase was partially flavin‐dependent. The pH and temperature optima for this enzyme were 9.8 and 40 °C, respectively. In addition, drought stress enhanced the activity under alkaline pH and high temperature conditions. These results suggest that a complex regulatory mechanism, associated with the NADPH oxidase‐H 2 O 2 system, is involved in the response of rice to drought stress.